ImageMagick is installed on the server I work. When I create a Photo product instance, if I see the properties of the image, several displays have been generated.
I would like to display a thumbnail with :<dtml-var expr="image(display='thumbnail')">  

but Zope generated the next error :
Error Type: AttributeError
Error Value: __call__

Traceback (innermost last):
  File /zope/Zope-2.5.0-solaris-2.6-sparc/lib/python/ZPublisher/Publish.py, line 150, in publish_module
  File /zope/Zope-2.5.0-solaris-2.6-sparc/lib/python/ZPublisher/Publish.py, line 114, in publish
  File /zope/Zope-2.5.0-solaris-2.6-sparc/lib/python/Zope/__init__.py, line 159, in zpublisher_exception_hook
    (Object: test_photo_imagemagick)
  File /zope/Zope-2.5.0-solaris-2.6-sparc/lib/python/ZPublisher/Publish.py, line 98, in publish
  File /zope/Zope-2.5.0-solaris-2.6-sparc/lib/python/ZPublisher/mapply.py, line 88, in mapply
    (Object: testimagemagick)
  File /zope/Zope-2.5.0-solaris-2.6-sparc/lib/python/ZPublisher/Publish.py, line 39, in call_object
    (Object: testimagemagick)
  File /zope/Zope-2.5.0-solaris-2.6-sparc/lib/python/OFS/DTMLMethod.py, line 127, in __call__
    (Object: testimagemagick)
  File /zope/Zope-2.5.0-solaris-2.6-sparc/lib/python/DocumentTemplate/DT_String.py, line 473, in __call__
    (Object: testimagemagick)
  File /zope/Zope-2.5.0-solaris-2.6-sparc/lib/python/DocumentTemplate/DT_Util.py, line 159, in eval
    (Object: image(display='thumbnail'))
    (Info: image)
  File <string>, line 2, in f

Thanks in advance for the help you can give to me.
William.